What to do if the Hayes Adapter shows 'USB' LED is not lit or 'Fail' on USB interface panel, or the CAPI2032.DLL file cannot start?
- JjenniferhuntAug 14, 2025
If the “USB” LED is not lit, “Fail” appears on the USB interface panel, or the CAPI2032.DLL file fails to start, it could be due to the ISDN USB TA not being ready or the PC not being USB-ready. Here are some troubleshooting steps: * Ensure the USB cable is securely connected to both the PC and a self-powered USB hub (if applicable), and verify the switch on the back of the TA is turned on. * Check your PC's hardware and software to confirm USB capability.